KR102200875B1 - Thermoplastic resin composition with improved impact resistance at low temperature, whiteness and laser marking - Google Patents

Abstract

A thermoplastic resin composition capable of laser marking while minimizing a decrease in whiteness in a polymer resin having excellent low-temperature impact resistance and a white background color is disclosed. The present invention (A) 60 to 99.3% by weight of a polycarbonate resin; (B) 0.1 to 20% by weight of an impact modifier having a core-shell structure; (C) 0.1-20% by weight of white filler; And (D) 0.00001 to 0.005 parts by weight of a colorant based on a total of 100 parts by weight of the (A) to (C) components. It provides a thermoplastic resin composition for laser marking comprising.

Description

Thermoplastic resin composition with improved impact resistance at low temperature, whiteness and laser marking}

The present invention relates to a thermoplastic resin composition for laser marking, and more particularly, to a thermoplastic resin composition with improved low-temperature impact resistance, whiteness, and laser marking properties.

Conventionally, as a method of using ink to display characters, pictures, symbols, etc. on a polymer surface, pad printing, silk screen printing, and the like are mainly used, and recently, a laser marking method using a laser device is mainly used.

The method of marking using ink has a disadvantage of poor printing precision or durability. The laser marking method is excellent in printing precision, durability, and work efficiency, but the quality of printing varies depending on the characteristics of the polymer, or expensive laser marking additives may be used.

Korean Patent Nos. 0576314 and 0697977 provide a technology for obtaining white marking on the surface of a polymer by adding 0.01 to 5.0 parts by weight of carbon black, 0.1 to 10 parts by weight of clay minerals, or 0.01 to 10 parts by weight of a silicate compound to an acrylic resin. Although disclosed, there is a problem in that the whiteness greatly decreases when 0.01 parts by weight or more of carbon black is added to the white polymer material, thereby reducing the color of the product appearance.

In addition, Korean Patent Registration No.0755292 discloses a technology capable of obtaining a bright color marking on a dark background, including copper chromite having a spinel structure in a polycarbonate resin and less than 0.05 parts by weight of carbon black. When used in a polymer of, there is a problem in that the whiteness decreases and the color of the product appearance decreases.

In addition, Korean Patent Registration No. 0339454 discloses a technology capable of laser marking by adding 0.01 to 40 parts by weight of titanium black, black iron oxide, iron sulfate, carbon black, etc., which can absorb lasers into an acrylic resin. When added in an amount of 0.01 parts by weight or more, the whiteness is greatly reduced, and there is a problem that the color of the product appearance is deteriorated.

In addition, Korean Registered Patent Nos.1179414 and 1283740 are technologies related to acrylic copolymers and compound products that reinforce chemical and heat resistance in the base resin, and improve laser marking performance through a colorant to mark white letters or figures. However, there is a problem in that it is difficult to compare the laser marking performance with respect to whiteness and clarity through self-evaluation, and to obtain a high-white product with the content of the present colorant.

In addition, Korean Patent No. 0521703 is a thermoplastic resin composition capable of clear laser marking by including a clay mineral and a high molecular weight surfactant in an acrylic resin, and the clay mineral has the advantage of improving the durability of the laser marking part, but laser There is a problem in that it is difficult to make a specific comparison by comparing whiteness and clarity relative to the marking performance through self-evaluation, and to obtain a high white product with the suggested colorant content.

The present invention is to provide a thermoplastic resin composition capable of laser marking while minimizing a decrease in whiteness in a polymer resin having excellent low-temperature impact resistance and a white background color.

The present invention in order to solve the above problems, (A) 60 to 99.8% by weight of a polycarbonate resin; (B) 0.1 to 20% by weight of an impact modifier having a core-shell structure; (C) 0.1-20% by weight of white filler; And (D) 0.00001 to 0.005 parts by weight of a colorant based on a total of 100 parts by weight of the (A) to (C) components. It provides a thermoplastic resin composition for laser marking comprising.

In addition, the polycarbonate resin provides a thermoplastic resin composition for laser marking, characterized in that the melt index (300 ℃, 1.2 kg load) is 5 ~ 40 g / 10min.

In addition, the impact modifier is at least one selected from the group consisting of methyl methacrylate-butadiene-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, and methyl methacrylate-siloxane copolymer. It provides a thermoplastic resin composition for.

In addition, the white filler provides a thermoplastic resin composition for laser marking, characterized in that at least one selected from the group consisting of titanium oxide, talc, zinc oxide, zinc sulfide and calcium carbonate.

In addition, the colorant is an organic pigment; Or organic dyes; Inorganic pigments selected from the group consisting of carbon black, graphite, graphene, carbon nanotubes, carbon nanofibers, titanium black and black iron oxide; Or it provides a thermoplastic resin composition for laser marking, characterized in that the inorganic dye.

In addition, the thermoplastic resin composition has a Color L value of 85 or more before laser marking and a color L change amount (ΔL) before and after laser marking measured according to the following method of 40 or more, and an IZOD room temperature impact strength (ASTM D256, 1/8 Thermoplastic for laser marking, characterized in that the "specimen, 23℃) is 70 kgf·cm/cm or more, and the IZOD low-temperature impact strength (ASTM D256, 1/8” test piece, -30℃) is 15 kgf·cm/cm or more Provides a resin composition.

[Measurement Method of Color L]

Measure the Color L value of the resin composition specimen using a color difference meter (Datacolor 850, SCI mode), and laser mark a 4 cm × 4 cm area on the specimen using a laser marking device (Fiber laser 1kw, IPG) (Speed: 800 mm/sec, Power: 60%, Frequency: 20 kHz, Pulse Width: 5 µs, Pitch: 0.05 mm), and then measure the color L value of the specimen.

According to the present invention, by containing an impact modifier having a specific composition of a core-shell structure in a polycarbonate resin, a white filler, and a colorant, the polymer resin having excellent low-temperature impact resistance and a white background color minimizes the decrease in whiteness while minimizing the decrease in whiteness and has laser marking properties. It is possible to provide an excellent thermoplastic resin composition for laser marking.

1 is a photograph exemplarily illustrating laser marking in a test example of the present invention.

Hereinafter, a preferred embodiment of the present invention will be described in detail. In describing the present invention, when it is determined that a detailed description of a related known technology may obscure the subject matter of the present invention, a detailed description thereof will be omitted. Throughout the specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components, unless otherwise stated.

In the conventional thermoplastic resin composition capable of laser marking, the present inventors have tried to use an additive in a polymer resin having a white background color, the whiteness is lowered or the laser marking property is lowered, leading to a decrease in the color of the product appearance, and low-temperature impact resistance is lowered. As a result of recognizing that there is a problem to be solved and repeated research to solve it, it has excellent low-temperature impact resistance by containing an impact modifier, a white filler, and a colorant having a specific composition of a core-shell structure in a polycarbonate resin, and a white background color. It was discovered that eggplant can have excellent laser marking properties while minimizing the decrease in whiteness in the polymer resin, and the present invention has been reached.

Thus, the present invention (A) 60 to 99.8% by weight of polycarbonate resin; (B) 0.1 to 20% by weight of an impact modifier having a core-shell structure; (C) 0.1-20% by weight of white filler; And (D) 0.00001 to 0.005 parts by weight of a colorant based on a total of 100 parts by weight of the components (A) to (C). It discloses a thermoplastic resin composition for laser marking.

The resin composition has a Color L value of 85 or more before laser marking and a color L change (ΔL) before and after laser marking of 40 or more, preferably a Color L value of 89 or more before laser marking, and laser marking measured according to the following method. Before and after Color L change amount (ΔL) is 45 or more, and IZOD room temperature impact strength (ASTM D256, 1/8" specimen, 23℃) is 70 kgf·cm/cm or more, preferably 72 kgf·cm/cm or more And IZOD low-temperature impact strength (ASTM D256, 1/8" specimen, -30℃) is 15 kgf·cm/cm or more, preferably 20 kgf·cm/cm or more, and has excellent low-temperature impact resistance, white In a polymer resin having a background color of, it is possible to have excellent laser marking properties while minimizing the decrease in whiteness.

[Measurement Method of Color L]

Measure the Color L value of the resin composition specimen using a color difference meter (Datacolor 850, SCI mode), and laser mark a 4 cm × 4 cm area on the specimen using a laser marking device (Fiber laser 1kw, IPG) (Speed: 800 mm/sec, Power: 60%, Frequency: 20 kHz, Pulse Width: 5 µs, Pitch: 0.05 mm), and then measure the color L value of the specimen.

Hereinafter, each component of the thermoplastic resin composition for laser marking according to the present invention will be described in more detail.

(A) Polycarbonate resin

The polycarbonate (PC) resin used in the present invention has excellent impact resistance, heat resistance, weather resistance, self-extinguishing property, flexibility, processability and transparency, and excellent weather resistance, maintaining high physical properties for a long period of time, and excellent heat resistance and cold resistance. Maintains performance despite changes.

The polycarbonate resin is a polymer of bisphenol A, and may have a weight average molecular weight (Mw) of 10,000 to 200,000, preferably 20,000 to 50,000. In addition, a branched chain may be used, and preferably 0.05 to 2 mol% of a tri or higher polyfunctional compound, for example, a trivalent or higher phenolic compound is added to the total amount of diphenol used for polymerization. The prepared polycarbonate thermoplastic resin may be used.

In addition, the polycarbonate resin (300° C., 1.2 kg load) is preferably 5 to 40 g/10min, more preferably 10 to 25 g/10min. When the melt index of the polycarbonate resin is less than 5 g/10min, the processing temperature may be high and thus molding may be difficult, and when it exceeds 40 g/10min, the strength may become weak.

On the other hand, the preparation of the polycarbonate resin used in the present invention can follow a commonly used manufacturing method, for example, by reacting dihydroxy phenol and phosgen in the presence of a molecular weight modifier and a catalyst. Alternatively, it may be prepared by using an ester interchange reaction of a precursor obtained by dihydroxy phenol and diphenyl carbonate.

In the present invention, the polycarbonate resin is included in an amount of 60 to 99.8% by weight in the total resin composition in consideration of the specific usage of the impact modifier, white filler and colorant to be described later, and the fluidity, impact resistance, and processability of the final thermoplastic resin composition, and is preferably It may be included in an amount of 80 to 99% by weight, more preferably 85 to 98% by weight.

(B) Impact modifier with core-shell structure

The impact modifier having a core-shell structure used in the present invention not only prevents lowering of the impact resistance of the final resin composition, particularly low-temperature impact resistance, but also has a desired white background color by combining the polycarbonate resin with a white filler and a colorant described later. It plays a role of minimizing the decrease in whiteness of the polymer resin and maintaining excellent laser marking properties.

The impact modifier having a core-shell structure may be formed by grafting an unsaturated monomer into a core structure of a rubber to form a shell, and preferably, the core is a rubber polymer polymerized with a diene monomer, an acrylic monomer, or a silicone monomer, As an unsaturated monomer wherein the shell is an acrylic monomer or an aromatic vinyl monomer, the shell may have a core/shell structure grafted onto the core.

Specifically, the material used as the core of the impact modifier may be selectively applied from butadiene rubber, ethyl acrylic rubber, butyl acrylic rubber, silicone rubber, or a material composed of a combination thereof, and an acrylic monomer composed with them, a styrene-based material. It may be a monomer or a copolymer composed of an acrylonitrile monomer. Examples of the core material include polybutadiene, butadiene-styrene copolymer, polyisoprene, butadiene-acrylonitrile copolymer, isobutylene-isoprene copolymer, ethylene-propylene rubber, acrylic rubber, urethane rubber, silicone rubber, etc. . In addition, the material used as the shell of the impact modifier may be a material composed of styrene-acrylonitrile, polymethyl methacrylate, or a combination thereof, or may be a copolymer. As a copolymer used as such an impact modifier, in the present invention, in terms of maximizing low-temperature impact strength and color improvement, methyl methacrylate-butadiene-styrene copolymer, acrylonitrile-butadiene-styrene copolymer or methyl methacrylate-siloxane copolymer The coalescence may be preferably selected, more preferably a methyl methacrylate-butadiene-styrene copolymer may be selected.

In the present invention, the impact modifier may be included in an amount of 0.1 to 20% by weight, preferably 0.5 to 10% by weight, more preferably 1 to 8% by weight in the total resin composition. When the content of the impact modifier is less than 0.1% by weight, there is no effect of improving impact resistance, and when it exceeds 20% by weight, the viscosity of the resin increases, resulting in poor processability.

(C) white filler

In the present invention, the white filler is for improving the hiding power and whiteness of the polymer and is not particularly limited, but is preferably selectively applied from titanium oxide, talc, zinc oxide, zinc sulfide, calcium carbonate, or a combination thereof. have.

In the present invention, the white filler may be included in an amount of 0.1 to 20% by weight, preferably 0.5 to 10% by weight, more preferably 1 to 8% by weight in the total resin composition. When the content of the white filler is less than 0.1% by weight, it is difficult to improve whiteness and hiding power, and when it exceeds 20% by weight, the mechanical properties of the resin are deteriorated.

(D) coloring

In the present invention, the colorant is not particularly limited to the color as long as it acts as a material for marking by absorbing the laser, and for example, a black or dark organic or inorganic pigment or dye may be preferably selected as the colorant.

The black inorganic pigment may be selectively applied from carbon black, graphite, graphene, carbon nanotubes, carbon nanofibers, titanium black, black iron oxide, or a combination thereof.

In addition, the black organic pigment and the organic dye are colored in the base resin by a combination of dyes having a complementary color relationship to each other to show a black series to be judged visually. The black series expressed here is not black that extremely blocks all wavelength bands, but represents a black series to be judged by the naked eye. For example, it can be expressed in black with red, black with blue, black with green, and black with purple. As usable organic pigments and dyes, Disperse Yellow 54, Disperse Yellow 201, Solvent Yellow 33, Solvent Yellow 63, Solvent Yellow 93, Solvent Yellow 98, Solvent Yellow 104, Solvent Yellow 114, Solvent Yellow 160, Solvent Yellow 163, Solvent Yellow 176, Solvent Yellow 188, Pigment Yellow 12, Pigment Yellow 14, Pigment Yellow 34, Pigment Yellow 83, Pigment Yellow 110, Pigment Yellow 138, Pigment Yellow 147, Pigment Yellow 180, Pigment Yellow 183, Pigment Yellow 184, Solvent Green 3, Solvent, Green 5, Solvent Green 28, Pigment Green 7, Pigment Green 36, Solvent Red 52, Solvent Red 135, Solvent Red 146, Solvent Red 149, Solvent Red 179 , Solvent Red 207, Pigment Red 41, Pigment Red 48:1, 48:2, 48:3, Pigment Red 57:1, Pigment Red 122, Pigment Red 149, Pigment Red 178, Pigment Red 181, Pigment Red 202, Pigment Red 254, Solvent Violet 13, Solvent Violet 31, Solvent Violet 36, Disperse Violet 26, Disperse Violet 31, Pigment Violet 19, Pigment Violet 23, Disperse Orange 47, Solvent Orange 60, Solvent Orange 63, Solvent Orange 64, Pigment Orange 71 and Solvent Blue 45, Solvent Blue 97, Solvent Blue 104, Solvent Blue 122, Pigment Blue 15, 15:1, 15:2 15:3 and 15: 4, Pigment Blue 60, etc. can be combined so that a black color can appear with the naked eye as a combination having a mutually complementary relationship. In addition, it is possible to express a black color even in a combination of the black pigment or dye.

In the present invention, the colorant is included in an amount of 0.00001 to 0.005 parts by weight, preferably 0.00005 to 0.004 parts by weight, more preferably 0.00005 to 0.001 parts by weight, based on 100 parts by weight of the (A) to (C) components. Can be included as When the colorant content is less than 0.00001 parts by weight, laser marking performance decreases, and when it exceeds 0.005 parts by weight, whiteness decreases.

In addition to the above-described main components, the thermoplastic resin composition for laser marking according to the present invention may further include an additive suitable for a desired use or effect. For example, dyes, pigments, heat stabilizers, UV stabilizers, antioxidants, lubricants, release agents, compatibilizers, flame retardants, fillers, antibacterial agents, biodegradants, etc., in addition to the above colorants may be additionally added and applied for various purposes.

Hereinafter, a specific example according to the present invention will be described.

First, the specifications of the components including the polycarbonate resin used in the examples of the present invention are as follows.

(A) Polycarbonate resin

Bisphenol A-type polycarbonate (PC-1100, Lottechem) having a melt index (300°C, 1.2 kg load) of 15 g/10min was used.

(B) Impact modifier with core-shell structure

(B-1) methyl methacrylate-butadiene-styrene copolymer (EM500, LG Chem), (B-2) acrylonitrile-butadiene-styrene copolymer (HR181, Kumho Petrochemical) and (B-3) methyl A methacrylate-siloxane copolymer (S-2001, Mitsubishi Rayon) was used.

(C) white filler

Siloxane coated TiO ₂ (Kronos 2233, Kronos)

(D) coloring

Columbian carbon black (Raven 1020) was used as a black pigment.

Example 1

(A) 95 parts by weight of a polycarbonate resin, (B-1) 2 parts by weight of an impact modifier having a core-shell structure, (C) 10 parts by weight of a white filler, and (D) 0.0001 parts by weight of a colorant were quantitatively mixed and mixed, The thermoplastic resin composition was made into pellets using a twin-screw extruder heated to 270°C to 300°C, dried at 100°C for 4 hours using a hot air dryer, and then injection molded using a mold for specimen production.

Examples 2 to 9, Comparative Examples 1 to 4

In Example 1, a specimen was molded in the same manner as in Example 1, except that the components (A) to (D) were adjusted to the content of Table 1 below.

Test example

For the specimens according to the Examples and Comparative Examples, the Color L value and the amount of change, the room temperature and low temperature impact strength were measured according to the following method, and the results are shown in Table 1 below.

[How to measure]

(1) Color L

Measure the color L value of the specimen using a colorimeter (Datacolor 850, SCI mode), and use a laser marking device (Fiber laser 1kw, IPG) on the specimen with a size of 4 cm × 4 cm (see Fig. 1). After laser marking (Speed: 800 mm/sec, Power: 60%, Frequency: 20 kHz, Pulse Width: 5 µs, Pitch: 0.05 mm), measure the color L value of the specimen, and before and after laser marking Color L The amount of change (ΔL) was calculated.

(2) Impact strength

According to ASTM D256 method, 1/8" specimens were measured for IZOD impact strength at 23°C and -30°C.

Referring to Table 1, first, when the polycarbonate resin according to the present invention contains an impact modifier having a core-shell structure of a specific composition, a white filler, and a colorant (Examples 1 to 4, 7 to 9), low-temperature impact resistance It can be seen that laser marking properties are excellent while minimizing the decrease in whiteness in the polymer resin that is excellent and has a white background color. Here, as the difference between the background color and the laser marking color increases, the visibility and clarity of the laser marking increase. However, when the content of the white filler is relatively excessive (Example 5), the impact strength at room temperature decreases slightly, and when the colorant content does not reach a certain level (Example 6), the laser marking property slightly decreases, It can be seen that there is an ideal component composition ratio for realizing the balance of all physical properties, such as improving impact resistance, minimizing reduction in whiteness, and improving laser marking properties.

On the other hand, when the colorant is not contained (Comparative Examples 1 and 2), the laser marking property is significantly lowered, whereas when the content is excessive (Comparative Example 3), the laser marking property is lowered as well as the whiteness. , It can be seen that when the impact modifier having a core-shell structure is not included (Comparative Example 4), the low-temperature impact resistance is significantly lowered.

The preferred embodiments of the present invention have been described in detail above. The description of the present invention is for illustration only, and those of ordinary skill in the art to which the present invention pertains will be able to understand that other specific forms can be easily modified without changing the technical spirit or essential features of the present invention.

Therefore, the scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning, scope, and equivalent concepts of the claims are included in the scope of the present invention. It must be interpreted.

Claims (6)

(A) 80 to 99% by weight of a polycarbonate resin;
(B) 0.5-10% by weight of an impact modifier having a core-shell structure;
(C) 0.5-10% by weight of white filler; And
(D) 0.00005 to 0.004 parts by weight of a colorant based on a total of 100 parts by weight of the components (A) to (C);
As a thermoplastic resin composition for laser marking comprising a,
The thermoplastic resin composition has a Color L value of 89 or more before laser marking and a color L change (ΔL) before and after laser marking measured according to the following method of 40 or more, and an IZOD room temperature impact strength (ASTM D256, 1/8" specimen , 23°C) is 72 kgf·cm/cm or more, and IZOD low-temperature impact strength (ASTM D256, 1/8" specimen, -30°C) is 20 kgf·cm/cm or more. :
[Measurement of Color L]
Measure the Color L value of the resin composition specimen using a color difference meter (Datacolor 850, SCI mode), and laser mark a 4 cm × 4 cm area on the specimen using a laser marking device (Fiber laser 1kw, IPG) (Speed: 800 mm/sec, Power: 60%, Frequency: 20 kHz, Pulse Width: 5 µs, Pitch: 0.05 mm), and then measure the color L value of the specimen. The method of claim 1,
The polycarbonate resin is a thermoplastic resin composition for laser marking, characterized in that the melt index (300 ℃, 1.2 kg load) of 5 ~ 40 g / 10min. The method of claim 1,
The impact modifier is at least one selected from the group consisting of methyl methacrylate-butadiene-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, and methyl methacrylate-siloxane copolymer. Resin composition. The method of claim 1,
The white filler is a thermoplastic resin composition for laser marking, characterized in that at least one selected from the group consisting of titanium oxide, talc, zinc oxide, zinc sulfide and calcium carbonate. The method of claim 1,
The colorant is an organic pigment; Or organic dyes; Inorganic pigments selected from the group consisting of carbon black, graphite, graphene, carbon nanotubes, carbon nanofibers, titanium black and black iron oxide; Or a thermoplastic resin composition for laser marking, characterized in that the inorganic dye. delete

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